Pressure sensors comprising semiconductor integrated circuits are known in the art. U.S. Pat. No. 6,221,023 discloses a pressure sensor mounted on the distal end of an intra-corporeal catheter which detects pressure applied on the sensor. The sensor includes a chip that becomes deformed in accordance with pressure applied thereto and a piezoelectric element or strain gauge, mounted on the chip that issues detection signals in accordance with the chip's deformation. The pressure is detected based on the issued signals. The sensor also includes a pressure transmitting element mounted distal to the chip, in this case the distal end of a catheter. The sensor chip comprises a disk-like sensing plate on which the strain gauges are integrally formed. Wires are connected to the strain gauges for electrical connection to pads on a separate substrate that is attached to the side of a flexible base. The pressure transmitting element transmits pressure applied to the catheter's distal end to the sensing plate and tilts the sensing plate in accordance with the pressure. The strain gauges issue detection signals according to the degree and the direction of the tilting. A disadvantage of the known pressure sensor is that only pressure via direct mechanical contact to the distal end can be detected.
U.S. Pat. No. 7,207,227 discloses a pressure sensor for detecting pressure without requiring direct mechanical contact, wherein a cavity or recess is provided in a semiconductor substrate and a diaphragm or membrane, which can be deformed by pressure, covers the cavity. A disadvantage of the known semiconductor pressure sensor is that it requires a complex fabrication process to provide for the separate membrane within the integrated circuit.